The invention relates to a method and a corresponding flax dressing machine having a breaking device for decorticating flax.
The harvesting process of the traditional flax line for the textile sector is directed towards obtaining a maximum fiber length in conjunction with uniform fiber length distribution and fibers arranged parallel. For these quality requirements the conduct of the dew retting of the pulled plants in the field and recognition of the correct gathering time are of decisive importance. The risk of losing the harvest is great and the period of time during which harvesting is possible, the so-called harvesting window, is extremely short and cannot be determined in advance because of the dependence of the biological dew retting process on weather.
Parallel laying of the pulled flax stalks in the field and the maintenance of this strict orientation during all subsequent intermediate mechanical steps in the field constitute another major feature of the traditional harvesting technique. This parallel orientation adds considerably to the difficulty of handling the material in the field. It was, however, hitherto unavoidable, not only in connection with the further dressing of the flax but also because of its influence on the retting process in the field. Good arrangement on the ground and a slight layer thickness ensured uniform retting.
According to the traditional line the fibers themselves are obtained by a process carried out in stationary equipment only after the stalk material has been gathered. Since the fibers amount to at most 20% of the weight of the stalks, 80% of the biomass was therefore transported unnecessarily.
From EP-A-0 332 726 a self-propelled flax harvesting device is known which already contains a breaking device in the form of numerous pairs of breaking rollers. It is thereby attempted to decorticate the flax straw already in the field, at least coarsely, and to strew the wood components over the field. However, here also the flax straw must be fed to the breaking device with an appropriate parallel alignment. If in this known machine a pick-up head is provided to pick up flax straw in tangled form, this means that the tangled, bent stalks must be realigned exactly parallel in the machine.
DE-A-37 35 235 also describes a flax harvesting machine having a breaking device for the woody inner core of the flax stems. Here also the stems are fed to the breaking device in an orderly, uniform manner.